x-apidog-enum
`x-apidog-enum` appears on schema objects and properties. Its value is a list. Used by 4 providers across 13 OpenAPI documents. It sits in the `x-apidog-` namespace, so its meaning is defined by apidog tooling rather than by OpenAPI. Consistent with type system — this is inferred from where the key appears and what it carries, not from any published definition.
Where it appears
| Location in the document | Occurrences | |
|---|---|---|
| schema | 50 | |
| operation | 1 |
What its value looks like
| Value shape | Occurrences |
|---|---|
| array | 51 |
Providers publishing it
All 4.
Why this is not in OpenAPI
Extensions exist because a provider needed something the specification would not carry. Most of what they hold is not the API contract at all — it is operational metadata about the contract: documentation, lifecycle, policy, provenance, and now agents. That metadata is usually better placed alongside the contract, in an Overlay or an APIs.json index, than crammed inside it. See everything else doing the data & schema semantics job.